The present invention relates to a configuration of a wireless terminal for communicating with a base station.
In the wireless communication using a wireless communication terminal (hereinafter referred to as a “terminal”) and a wireless communication base station (hereinafter referred to as a “base station”), there are various communication standards. In the third-generation mobile phone (3G), the communication standards such as CDMA2000 and W-CDMA using the CDMA scheme have become main stream. This CDMA scheme achieves simultaneous connections by incomparably more users than before by using a frequency band or time widely without dividing them, and meets also the data communication speed requirement in recent wireless communication.
However, since the CDMA scheme, due to characteristics of achieving simultaneous connections by many users, causes the Near-Far Problem: “in the same time and the same frequency, the strong radio signal which a terminal near a base station transmits drowns out radio signal from a terminal far from the base station, and as a result, the base station is difficult to receive radio signal from the terminal far from itself.” This problem is solved by executing the power control for increasing the power of radio signal which the terminal far from the base station transmits and decreasing the power of radio signal which the terminal near the base station transmits, so that the power of radio signal from any terminal which the base station receives becomes nearly constant. It should be noted that the power control is executed in a very short cycle, such as 800 times/second in CdmaOne and CDMA2000, and 1500 times/second in W-CDMA.
On the other hand, in the CDMA scheme, it is intended to effectively utilize resources required to transmit and receive data by using a no-traffic monitoring function. The no-traffic monitoring function changes the status of the call in a terminal from “a connected state” for transmitting synchronization signal to the base station to “a disconnected state” for only receiving radio signal from the base station, when a certain period has passed in a no-traffic state since the terminal went into the no-traffic state.